1. Field of the Invention
The present invention relates to a method and apparatus for controlling power supply. More particularly, the present invention relates to a method and apparatus for supplying some of the required supply power or additionally using some of the surplus power by estimating and adjusting power usage or power consumption.
2. Description of the Related Art
General power systems are operated such that power supply may be adjusted to correspond to power demand. For this purpose, a variety of power supply control techniques, such as a power demand forecasting technique, an economic load dispatch technique and an automatic load dispatching control technique, have been devised and used.
Power supply systems, also known as generators, are generally built in a large scale in consideration of the economy of scale, and the reliability and cost savings are considered as their primary operating criteria. In recent years, however, the demand for power has surged and a type of power load has changed significantly from linear loads, which are proportional to the frequency, to nonlinear loads such as digital devices. In addition, it is difficult to build existing large-scale power generation systems due to the site selecting and massive investment risks. Due to these situations, an interest in the role of the demand side has increased, in matching the demand and supply of power and operating the power systems reliably.
The general demand-side power supply resources include, for example, renewable energy resources, and demand response resources such as for example, power storage apparatuses and electric cars. These demand response resources may be part of an apparatuses that can adjust power usage, such as smart appliances. The renewable energy resources refer to solar or wind power generation apparatuses which are installed on a small scale at a home or in local areas. The power storage apparatus refers to an apparatus that can store power in advance and supply the stored power if necessary, like a battery. The electric car is similar to the power storage apparatus in terms of the principle of operation since it basically uses a battery. However, the electric car is distinguishable from the power storage apparatus installed in a fixed position, since the car has additional mobility. Apparatuses that can provide these demand-side power supply resources may match the demand and supply of power in the power system reducing the power usage if the power system lacks available supply power, and increasing the power usage if the power is oversupplied from the power system.
Among the apparatuses that can provide the demand-side power supply resources, a demand response apparatus capable of acquiring demand response resources may save power by reducing power usage by changing a reference value of its operation if the power system lacks power, thereby making it possible to supply power when necessary. In addition, the demand response apparatus may adjust its ongoing or scheduled operation in the time axis, thereby making it possible to secure the power it will supply in a time interval in which power is required.
In addition, if the power is oversupplied from the power system, the demand response apparatus may increase power usage by changing a reference value of its operation, or adjust its ongoing or scheduled operation in the time axis, thereby increasing the power usage in the time interval where the power is oversupplied.
On the other hand, if the power system lacks power, the demand response apparatus may perform the following operation. As an example, if the demand response apparatus is an air conditioner, the demand response apparatus may reduce the power usage by changing the set temperature, which is a reference value of its operation, to 27° C. from 25° C., and supply the power that is acquired to correspond to the reduced power usage. As another example, if the demand response apparatus is a washing machine, the demand response apparatus may delay the dehydration operation, which is a reference value of its operation, by 20 minutes, to thereby acquire the power required for dehydration for the delayed 20 minutes.
In this way, conventionally, the demand response apparatus may control power supply by decreasing or increasing the power usage. However, no technical measures have been provided to determine in which way the demand response apparatus should receive a signal indicating the need for power supply, to determine in which way the apparatus should measure the available supply power, to determine in which format the apparatus can represent information about the available supply power, and to provide an interface for allowing users to set an operation of the demand response apparatus in a specific way.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.